‘Normally we would see this among young adults as they start to develop hay fever but we are starting to see more of it among young children. As there is more allergy, the severity seems to be increasing and the patterns are changing.’

Schoolboy Jack Harrison is allergic to most types of fruit. A banana can bring him out in a rash.

And even the tiniest piece of celery in a salad can leave him gasping for breath.

‘I can eat some types of apples, as well as blackberries and raspberries - but beyond that I can’t eat any of the fruits most people eat: oranges, pears, bananas, most type of apples,’ said the 15-year-old from Wymondham in Norfolk.

Both Jack and his seven-year-old brother Jerome suffer from fruit allergies. Their intolerance is linked to pollen from birch trees.

‘There are times when it is so annoying and you wish you could eat what everyone else can,’ says Jack. ‘If someone has a banana or something I think - yeah that’d be nice.

‘It’s difficult because it makes it much harder to get my five a day. I have to work hard to get just two or three.’

Their mother Margaret says the allergies make life more complicated - and more expensive.

‘The anxiety is they’re not getting enough nutrients. They can’t have school dinners, and I have to supply food if they go to someone’s birthday party. If they eat out they can have a baked potato - and that’s about it. Celery is lethal so you can’t just pick what you want out of the salad bar.

The allergies first became apparent when Jack was as young as 18 months, but it was not until he was 10 that the full list of problematic foods became apparent.

Comments from the Daily Mail’s website:

Our bodies are certifiable toxic waste. within an environment riddled with tens of thousands of new chemicals. most poorly understood in terms of interaction in our bodies and the environment. We still have the natural suspects (mercury, lead, etc.). And most susceptible to damage is the growing fetus. The wonder is that anyone is still healthy.